A cup bra size
The letter A stands for a difference of 1 in between your bust and your band, printed as A on US, UK, EU, FR/BE and AU/NZ tags.
In US sizing a A cup is a difference of 1 in (2.5 cm) between bust and band.
A at 1 in, system by system
A cup letter stands for a difference between bust and band. The same letter sits at a different difference in some systems.
| System | Difference (in) | Difference (cm) | Written as |
|---|---|---|---|
| US | 1 | 2.5 | A |
| UK | 1 | 2.5 | A |
| EU | 1 | 2.5 | A |
| FR/BE | 1 | 2.5 | A |
| AU/NZ | 1 | 2.5 | A |
| JP | Not used | Not used | Not used |
| EU method (cm) | Measured in cm | 12 to 14 cm | A |
Where sources disagree about A
The sources used here agree on this letter. They differ on other points, which the methodology page lists.
9 sizes carry a A cup
Every size page that has this cup.
Across the six systems, A is the quietest row: five print A at 1 in, and JP prints no letter at that difference. The US figure is 2.5 cm.
Your A sits one step above AA, which stands for 0 in, and one step below B, which stands for 2 in. Every system that prints A names the same neighbours.
The EU method gives A a range of 12 cm to under 14 cm. JP letters vary by brand and its chart lists them for only part of the range, so A has no JP entry.
Your bust for A runs 32.5 to 33.5 in on band 32 (82.6 to 85.1 cm), 34.5 to 35.5 in on band 34, 36.5 to 37.5 in on band 36 and 38.5 to 39.5 in on band 38.
Sister sizes of 34A are 32B and 36AA, and sister sizes of 36A are 34B and 38AA. The published charts show no disagreement here beyond the missing JP letter.
Questions
What does a A cup mean?
A A cup is a difference of 1 in (2.5 cm) between bust and band in US sizing. The letter names the size of that difference.
Which difference is a A cup in each system?
US 1 in, UK 1 in, EU 1 in, FR/BE 1 in, AU/NZ 1 in and JP does not use it.
Do all systems write a A cup the same way?
Not everywhere. In US sizing it is 1 in, and JP (not used) differ.